Rodents and other research animals are flown in space in animal module enclosures to provide model systems for studying the metabolic and physiological changes that occur when humans are exposed to microgravity. It is therefore important that investigators are confident that the changes which they see in these animals while in space are in fact due to microgravity, and not some other, unidentified condition(s). A nutritional deficiency, whether due to dietary inadequacy or insufficient intake, is one factor that could lead to experimental results which are difficult to interpret. This is especially significant since nutrient imbalances often mimic the response conditions encountered during space adaptation. For example, Gemini, Apollo, and Skylab astronauts consistently exhibited symptoms of altered calcium homeostasis.
In order to be assured that experimental results are not confounded, or masked, by nutritional deficiencies, investigators must therefor be assured that adequate intake of a nutritionally balanced diet (including water) is achieved by research animals. Previously flown flight hardware has been lacking in sufficient, quantitative intake monitoring capabilities. At times, daily intake had to be estimated by total consumption over the entire mission. Jammed feeders, and feed wastage due to crumbling of the hard food, effected reliability. Also, the use of natural ingredient diets minimized the ability to quantify, and/or control, the intake of single nutrients.
Additional problems with previously flown flight hardware include those of biocontainment of the housing system and diet sterility. The future of animal research in space was seriously jeopardized when animal by-products got into the cabin during a space flight. Biocontainment is thus a necessity for animal enclosure modules of this type.